Spatial and seasonal variation in pollution from pharmaceuticals and personal care products and the ecological risks in the Upper Paraná River Basin, Brazil

Both pharmaceuticals and personal care products (PPCPs) contaminate river water in Brazil. To determine the extent of such contamination in the rivers and tributaries of important basins in the state of Mato Grosso do Sul, Brazilian Midwest, this study aimed to examine the distribution of PPCPs in these waterways and then perform an ecological risk assessment (ERA). To accomplish this, water samples were collected from four river basins and their sub-basins, all of which are located in the southern part of the Brazilian state of Mato Grosso do Sul. PPCP concentrations were quantified, along with assessments of the in situ physicochemical characteristics of the water. ERA was evaluated as a risk quotient (RQ) based on the maximum measured concentration of PPCPs in the samples. The relationship among the concentrations of PPCPs in aqueous samples was examined to assess the distribution of these substances in the environment. The highest concentrations of PPCPs involved caffeine, particularly during the dry season, indicating an intense route of contamination at sampled sites. Among other compounds, pharmaceutical compounds such as diclofenac, ibuprofen, and naproxen were prevalent, especially during the dry season, albeit in slightly lower concentrations. RQ results showed that most compounds investigated represent moderate to high toxicological risk to the aquatic ecosystem. These results suggest that PPCPs are widely distributed in the studied area and provide a benchmark for comparison, or starting point, for future monitoring and environmental recovery programs, as well as encouraging revisions to current legislation.